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Supply Curve: Definition, Features, and Determinants

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Definition of Supply Curve

The supply curve shows the relationship between price and quantity supplied. As price increases, suppliers offer more units for sale because each unit can be sold at a higher selling price. The higher selling prices are offset by the increased costs associated with making additional goods available to buyers or consumers. For example, assume that you are a supplier of widgets. You can sell each widget at a price of 10 dollars each. When you raise the price to11 dollars, then customers may demand that you produce more units before they buy from you. 


Law of Supply

Before proceeding with the supply curve, a little grounding is needed on the law of supply. The Law of Supply is a basic theory in Economics that lays down that price increase would necessarily lead to the supplied quantity of goods or services when all factors remain constant.  The supply curve slopes upward. It graphically represents the Law of Supply. Suppliers will increase production with an increase in prices, and the same is depicted in the upward curve.  


For individual suppliers, aggregate supply is determined by the supply curve. A supply schedule can be framed for this purpose. The schedule would go on to show that at a particular price point, there is a corresponding quantity supplied. When all individual quantities are plotted, it makes up for an aggregate supply curve. 


Determinants of Supply Curve

Price of Input

Input price has a major bearing on the supply curve. The costs of input are also known as 'Factors of Production’. Such input includes materials, labour, machinery used for the production of services and goods. The costs can be further divided into explicit and implicit costs. Explicit costs would include the price of labour and material, while implicit costs would comprise interest, rent, etc. While the former is paid out of pocket, the latter is considered to be an opportunity cost.


Technology 

Technology has a direct impact on production costs as innovation is likely to cause higher productivity as well as cut down existing costs. Wasteful expenditure can also be conserved. All these will help to decrease input costs. However, the converse may also take place with technological decay. The efficiency of production, in that case, would come down. Hence, technology improvement will cause an increase in supply, and technology decay will cause a decrease in supply.


Number of Producers 

A greater number of producers automatically increases the supply. When a greater number of firms enter the market, there is an increase in supply. On the other hand, when a number of firms leave the market, there will be a decrease in supply. One should note that the entry of new firms would alter the demand schedule in the market. This may either put pressure on existing firms or affect their operations, thus causing a decrease in supply.


Expectations 

Production decisions are significantly affected by the expectations of supply price. Production would only be enhanced by firms when there is a reasonable expectation of a higher market price. Such expectation is generated based on certain credible evidence. Hence, if there is an expectation of a price rise, there will be an increase in supply. On the contrary, if there is an expectation of price fall, there will be a decrease in supply.


Movement along the Supply Curve 

The supply curve in Economics also exhibits movement along the curve. Movement along the supply curve is the graphical representation of alterations in goods or services supply on account of its price when all other factors remain constant. If there is a price change, supply also changes. The movement will be from one point to another point on the same supply curve. Movement can be both rightward and leftward. 


Rightward Movement 

The above figure shows that with price rise, more revenue is generated per unit if all other factors remain constant. Hence, to earn more profit, firms will supply more. This is termed as expansion in supply.


Leftward Movement

The above graphical representation also shows that with a fall in price, firms tend to make less revenue, which automatically contracts supply. In this case, movement becomes evident by movement from a right side point to that of a left side point on the given supply curve. 


Supply Curve Shift 

The shift in the supply curve will take place with the change of any of the determinants. For instance, with a change in costs, the supply curve will shift the position. With a rise in cost, production becomes less at a given price — the supply curve shifts to the left. The decrease in costs means that there can be more productivity, which will result in a right-side shift in the supply curve. 


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Conclusion

The conclusion of the article is that an increase in supply is likely to be seen with technological innovation, entry of new firms, and expectation of price rise. Meanwhile, a decrease in supply can be witnessed due to technological decay, the exit of existing firms, and the expectation of price fall. There are many factors that affect the production and hence, supply. Hence, a change in any of the determinants may result in a shift in the supply curve. One should ensure to adopt these methods to increase supply.

  • Cut down existing costs. Wasteful expenditure can also be conserved. All these will help to reduce the cost of production.

  • Make efforts to expand technology or technology used in production. This will increase supply by expanding productive capacity.

  • Seek to improve the quality and quantity of input employed for production, if not already done so. Improvements in these factors will result in increased output and hence, supply. 

  • Ensure that there is a level of investment in production. Without any investments, supply cannot be increased. All these changes will aid to increase supply and hence, prove profitable for one's business.

  • Seek assistance from our professionals at Vedantu! We have a team of experts who can assist you with the concepts as well as application aspects of Economics.


If you are looking for a tutor in Economics, get in touch with Vedantu! We have experienced tutors who can help you learn Economics. Download the Vedantu App now on your mobile device- iPhone, Android, or Windows 10.

FAQs on Supply Curve: Definition, Features, and Determinants

1. What is a supply curve in Economics?

A supply curve is a graph that illustrates the relationship between the price of a good or service and the quantity of that item that a producer is willing and able to sell. It graphically represents the Law of Supply, which states that, ceteris paribus (all other factors being equal), as the price of a product increases, the quantity supplied also increases.

2. What are the main features of a typical supply curve?

A standard supply curve has two primary features:

  • Positive Slope: It slopes upwards from left to right, indicating a direct or positive relationship between price and quantity supplied.
  • Price and Quantity Axis: The vertical axis (Y-axis) represents the price of the product, while the horizontal axis (X-axis) represents the quantity supplied.

3. What are the key determinants that cause a shift in the supply curve?

A shift in the entire supply curve is caused by a change in factors other than the good's own price. The key determinants include:

  • Input Prices: Changes in the cost of raw materials, labour, or machinery used for production.
  • Technology: Technological advancements typically lower production costs and increase efficiency, shifting supply to the right.
  • Number of Sellers: An increase in the number of firms in the market increases supply, while firms exiting the market decrease it.
  • Expectations of Future Prices: If producers expect prices to rise in the future, they may decrease current supply to sell more later at a higher price.
  • Government Policies: Taxes on production increase costs (shifting supply left), while subsidies decrease costs (shifting supply right).

4. How is a 'movement along the supply curve' different from a 'shift in the supply curve'?

The distinction is crucial: a movement along the supply curve occurs only when the price of the good itself changes, leading to a change in the quantity supplied. This is shown as moving from one point to another on the same curve. In contrast, a shift in the supply curve happens when a non-price determinant (like technology or input costs) changes, causing the entire curve to move either to the right (increase in supply) or to the left (decrease in supply).

5. Why does the supply curve generally slope upwards?

The upward slope of the supply curve is a direct consequence of the Law of Supply and the profit motive. As the market price of a good rises, it becomes more profitable for firms to produce and sell that good. The higher price covers the potentially higher marginal costs of producing additional units, incentivising producers to increase their output to maximise their revenue and profits.

6. How does an improvement in technology affect the supply curve?

An improvement in technology leads to a rightward shift in the supply curve. This is because technological advancements often increase productivity and lower the average cost of production. As a result, firms can produce more output at every price level, or they can produce the same quantity at a lower cost, effectively increasing the overall supply in the market.

7. What is the difference between an individual supply curve and a market supply curve?

An individual supply curve represents the quantity of a good that a single, specific firm is willing to sell at various prices. A market supply curve, on the other hand, represents the total quantity of a good that all firms in the market combined are willing to sell at those same prices. It is derived by horizontally summing the individual supply curves of all producers in the market.

8. Can a supply curve ever slope downwards?

While highly uncommon for most goods and services, a downward-sloping supply curve can exist in specific, exceptional cases. The most cited example is the backward-bending supply curve of labour. At very high wage rates, an individual may choose to work fewer hours (supply less labour) because they can afford more leisure time while still meeting their income goals. However, for typical product markets studied in Class 11 and 12 Economics, the supply curve is assumed to be upward sloping.

9. How do government policies like taxes and subsidies act as determinants of supply?

Government policies directly influence a firm's cost of production. A tax on production acts as an additional cost, making it less profitable to produce at any given price; this causes the supply curve to shift to the left (a decrease in supply). Conversely, a subsidy is a payment from the government that lowers production costs, making it more profitable to produce. This causes the supply curve to shift to the right (an increase in supply).